The exacerbation and maintenance of chronic pain are linked to spousal criticism/hostility, yet the nature of such links is poorly understood. Research in this area is largely correlational, leaving causal directions indeterminate, and theoretical models do not specify mechanisms through which spouse criticism/hostility and patient pain are related. We propose that links between spousal criticism/hostility and patient adjustment to chronic low back pain (CLBP) may be illuminated through a synthesis of an Expressed Emotion (EE) model, in which spousal criticism of how the patient is managing their condition and spousal criticism/hostility toward the patient undermine patient adjustment, and an interpersonal model, in which persistent and exaggerated signs of poor adjustment by patients elicit critical/hostile reactions from patients'spouses. We propose that chronic pain symptoms elicit negative spouse responses and that such responses then worsen and maintain symptoms;a vicious spiral, which leads to poor adjustment. Because the cause of CLBP is often poorly understood by patient and spouse, unlike disease-related pain conditions (eg, cancer), CLBP provides a particularly appropriate model in which to test links between spouse and patient behaviors. Studies 1a and 1b will test the validity of causal pathways linking spousal criticism/hostility with patient behavior and mood described by EE and interpersonal models. Both studies will test 84 CLBP patients and spouses. In Study 1a, couples will engage in 2 marital discussions (neutral;conflictual), and then patients will undergo a Structured Pain Behavior task (SPBT) while the spouse observes. In Study 1b, spouses will observe patients undergo 2 activity tasks (neutral;SPBT), and then couples will engage in a conflictual marital discussion. If the 2 models explain links between spousal criticism and patient adjustment, then the relation between initial spouse criticism during the conflictual discussion will predict later patient pain behavior during the SPBT, and initial patient pain behavior during the SPBT will predict degree of later spouse criticism during the conflictual discussion. Study 2 will also evaluate the validity of the EE and interpersonal models, but a daily diary method will be used (N=84 patients and spouses). Patients and spouses will be given Personal Data Assistants (PDAs). For 14 days they will be prompted 5 times/day to respond to questions about their own and their spouse's mood and behavior, and contacts with their spouse during the preceding interval. Multilevel modeling of concurrent and lagged associations will allow testing within-spouse individual differences and between- spouse directionality of criticism and patient adjustment. Support for the spiral would be indicated by lagged within-dyad associations between patient pain behavior at Time 2 and spouse criticism at Time 3 among dyads who recorded high levels of conflict at Time 1. CLBP is a common and disabling condition. Learning more about links between spousal criticism/hostility and patient adjustment will provide information that could lead to development of novel, couples-based interventions to reduce pain and disability in this population. Public Health Relevance Paragraph: Exacerbation and maintenance of chronic pain are linked to spousal criticism and hostility, yet the nature of such links is poorly understood. We propose that the nature of the relationships between spousal criticism/hostility and patient adjustment to chronic low back pain (CLBP) may be illuminated through a synthesis of an Expressed Emotion (EE) model (spousal criticism of the patient undermines patient adjustment), and an interpersonal model (persistent signs of poor adjustment by patients elicit critical reactions from spouses). With 3 studies, we intend to learn more about links between spousal criticism/hostility and patient adjustment in order to could encourage development of clinical interventions and productive translational efforts targeting this relatively neglected area.